1. Climate Observations Stable Isotope Analysis
• 16O and 18O Isotope Analysis
- Oxygen isotope ratio (18O) is a measure of the ratio of heavy oxygen
(18O) to light oxygen (16O)
- Used as a proxy measure for paleotemperature
- More negative values indicate “colder” temperatures
• 12C/13C and 15N/14N Isotope Analysis
- “You are what you eat”, thus the building blocks that make your body,
have been taken from foods you have eaten over your lifetime.
- Specifically, the elements C and N in your bone are the same C and N
atoms that were in the foods you ate.
- Again we can measure the ratio of C isotopes and N isotopes to create
13C and 15N values similar to the 18O ratio above
mprichar/PRGIntrotoIsotopes.html

2. Climate Observations Stable Isotope Analysis (Con’t)
• 12C/13C and 15N/14N Isotope Analysis (Con’t)
- 13C and 15N values of various foods are fairly well known
- 13C and 15N values are signatures specific to different types of foods,
- Measuring the 13C and 15N values of your bone, we can infer from what
foods the bone C and N came
- Why bone - its is best preserved over time
- Analysis of the extracted protein portion of the bone, collagen, (and for
radiocarbon dating) reflect the protein part of our diets
- Adult collagen in our bones is constantly being replaced and completely
turned-over in about 10 years

3. Climate Observations Stable Isotope Analysis (Con’t)
• 12C/13C and 15N/14N Isotope Analysis (Con’t)
- 13C indicates how much marine protein (e.g., fish, shellfish) was in the
diet, compared to terrestrial proteins (e.g., grains, breads, cattle meat and
milk)
- 15N indicates how much plant food
was in the diet, compared to animal
foods (like meat and milk)
- Typical collagen isotope values
Holocene Western Europe
> 13C distinguishes between
terrestrial (-20%) and marine
(-12%) ecosystems
> 15N of terrestrial herbivores
are approximately 5%,
terrestrial carnivores are at about 9%
> For omnivores like humans the 15N indicates if they are behaving
more like herbivores (plant protein) or carnivores (animal protein)
PRGIntrotoIsotopes.html
Terrestrial
Ecosystems
fish
15N
carnivore
shellfish
herbivore
Marine
Ecosystems
13C

4. Climate Observations Stable Isotope Analysis (Con’t)
• Example - Ice Core Analysis
- 18O (green line) and
glacial ice accumulation
(blue line) for 10,000-
17,400 y B.P.
> Colder climate
associated with lower
accumulation values
> Note how quickly the climate shifted from cold to warm phases during
the glacial-interglacial transition
> Research suggests that major climatic changes such as these may
have occurred over just a few years, i.e., climate during the last
glacial period was inherently unstable and subject to rapid
fluctuations
> The last 10,000 years have been the most consistent and stable
climate in the 200,000 Greenland ice record
> This same period appears to have been less stable at lower latitudes
slideset/15/15_292_slide.html
Periods of Rapid Change
Accumulation (m ice / year)
18O
Years Before Present

5. Climate Observations Stable Isotope Analysis (Con’t)
slideset/20/20_409_slide.html
Stable Isotope Analysis (Con’t)
• Example - Ice Core
Analysis (Con’t)
- Quelccaya ice
cap (5,670 m
altitude; 164 m
thick) provides
clues about
South American
tropical climatic
variability
- Note Little Ice Age is identified in the 18O between

6. Climate Observations Stable Isotope Analysis (Con’t)
• Example - Coral Analysis
- Ambient water conditions (i.e., Sea Surface Temperature (SST) and,
possibly, fresh water influx and precipitation) when a layer of coral
skeletons was deposited determine the 18O within ice cores). Thus,
analyses of 18O can yield information about past water conditions
- Note that red spikes
(high 18O anomaly)
in 18O correspond
to the red spikes
(high SST anomaly)
in SST
- Yellow zones
indicate El Nino/
Southern Oscillation
(ENSO) warm
phases
- Coral records can
yield information
years into
the past in many tropical areas
slideset/13/13_240_slide.html
SST Anomaly (°C)
18O Anomaly

7. Climate Observations Palynology
• Pronounced pal-ih-nol-o-jee, the "a" as in "map”
• “Palyn” comes from a Greek word that means “I sprinkle” that is also a cognate
of the Latin word “Pollen” which means dust or fine flour.
• Branch of science dealing with microscopic (5 m to about 500 m), decay-
resistant remains (such as pollen and spores, living and fossil) of certain plants
and animals
Figs Examples of pollen from
flowering plants. Scale bar = 10 µm.
Fig. 9. Pollen from a cone-bearing
plant (e.g., pine). Scale bar = 10 µm.
Reference
Milne, L., 1998: Forensic Palynology.
Pollen and spores, Nature's Fingerprints
of Plants.

8. Climate Observations Palynology (Con’t)
• Lennart von Post (1916) suggested that buried sediments of fossil pollen was
a precise method for determining past vegetation regimes and cycles of
vegetation change
- Many plants produce great quantities of pollen or spores that are dispersed
by the wind
- Pollen and spores have very durable outer walls that can remain preserved
for thousands or even millions of years
- Unique morphological features of each type of pollen and spore remains
consistent within each species, yet each different species produces its own
specific form
- Each pollen and spore-producing plant is restricted in its distribution by
environmental conditions that include moisture, temperature and soil type
- Most wind-dispersed pollen and spores rarely travel very far before falling
to the surface
• Thus, by counting a sufficient number of fossil pollen and spores recovered
from each stratum in a deposit, one could reconstruct the types and abundance
of plants represented by those fossil grains

9. paleo/slides/slideset/16/
Climate Observations
Midden Analysis
• Middens are amalgamations of plant and
animal remains encased in crystallized packrat
urine
• First noted by military and scientific expeditions
in the West as early as 1849
• During 1960s paleoecologists began to fully
recognized potential for reconstructing past
environmental change
• Packrats or woodrats gather and accumulate plant
materials typically within 100 m of their den in dry
caves and crevices
• Plant remains and other debris (including insect and
vertebrate remains) are cemented into large masses
of crystallized urine that can persevered for tens of
thousands of years
slideset/16/16_307_slide.html
Bushy-tailed woodrat
paleo/slides/slideset/16/
16_308_slide.html

10. Climate Observations Midden Analysis (Con’t)
slideset/16/16_313_slide.html
Midden Analysis (Con’t)
• Thus, midden materials represent the local
environment when material was collected
• Middens tend to be preserved in some
environments better than others; arid
climates good
• Midden analysis locations

11. Climate Observations Midden Analysis (Con’t)
slideset/16/16_316_slide.html
Midden Analysis (Con’t)
• Results for 89 Packrat Middens
- Elevation zones for vegetation has
shifted over the last 24,000+ years
in the Grand Canyon

12. Climate Observations Midden Analysis (Con’t) • Summary - Plants have
shifted upward
on the Colorado
Plateau from last
glacial period
to the present
- During the last
glacial period,
the timber line
was lower than
today
- Also tree species
have shifted
upward
slideset/16/16_320_slide.html

13. Climate Observations Sediment Analysis
• North Atlantic oceanic sediment cores are used
to understand climatic variations during and
since the last ice age but not just confined to
local regions of the northeastern Atlantic
• Analyze cores by counting the number of both lithic (rock) and
plankton shell fragments
• Total number of particles fluctuate with climate changes
• Analysis of long cores indicate that plankton fragments dominated
(warm periods) for long stretches of time, while rock sediments
(cold periods) dominated in six spikes
• These sudden changes in sediments (referred to as Heinrich
events; cold events) are also visible in X-rays of sediment cores
as sharp transitions between dark-colored (plankton-dominated)
and light-colored (lithic-dominated) segments

14. Climate Observations Sediment Analysis • What could cause
these different
sediments?
- Heinrich events:
A significant SST
drop occurs;
reduces plankton
fragments;
extends the ice
sheet onto the
continental shelf;
icebergs with lithic
material breakoff; float off and melt depositing lithic material over ocean
bottom
- Non-Heinrich events: Deposited during warm periods with more plankton
material and fewer icebergs to transport lithic material